Liang Xiao, Yan Zhi-Ping, Han Hua-Bo, Wu Zheng-Guang, Zheng You-Xuan, Meng Hong, Zuo Jing-Lin, Huang Wei
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.
Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, 211800, P. R. China.
Angew Chem Int Ed Engl. 2018 Aug 27;57(35):11316-11320. doi: 10.1002/anie.201806323. Epub 2018 Jul 30.
Multi-resonance induced by boron and nitrogen atoms in opposite resonance positions endows a thermally activated delayed fluorescence (MR-TADF) emitter with a strikingly small full width at half maximum of only 26 nm and excellent photoluminescence quantum yield of up to 97.48 %. The introduction of a carbazole unit in the para position of the B-substituted phenyl-ring can significantly boost up the resonance effect without compromising the color fidelity, subsequently enhancing the performances of the corresponding pure blue TADF-OLED, with an outstanding external quantum efficiency (EQE) up to 32.1 % and low efficiency roll-off, making it one of the best TADF-OLEDs in the blue region to date. Furthermore, utilizing this material as host for a yellow phosphorescent emitter, the device also shows a significantly reduced turn-on voltage of 3.2 V and an EQE of 22.2 %.
处于相反共振位置的硼和氮原子诱导产生的多共振赋予了一种热激活延迟荧光（MR-TADF）发光体仅26 nm的半高宽，这一数值非常小，并且具有高达97.48%的优异光致发光量子产率。在B取代苯环的对位引入咔唑单元可以在不影响颜色保真度的情况下显著增强共振效应，进而提升相应纯蓝色TADF-OLED的性能，其具有高达32.1%的出色外量子效率（EQE）以及低效率滚降，使其成为迄今为止蓝色区域中最佳的TADF-OLED之一。此外，将这种材料用作黄色磷光发光体的主体，该器件还显示出显著降低的3.2 V开启电压和22.2%的EQE。
